Bazel: Update bazlets to latest stable-2.15 to use 2.15-rc3 API

Change-Id: I004544523de78a75da0b2051e1b3c2393b1b4ff9
diff --git a/WORKSPACE b/WORKSPACE
index 027abfd..6ca058c 100644
--- a/WORKSPACE
+++ b/WORKSPACE
@@ -3,7 +3,7 @@
 load("//:bazlets.bzl", "load_bazlets")
 
 load_bazlets(
-    commit = "66fa042963d9799faf7b29c273962f5c50884df6",
+    commit = "34d5ef186f73c80e61dcfa057ee400b2725164bf",
     #    local_path = "/Users/dpursehouse/git/bazlets",
 )